missing visio text in powerpoint slide

Westbend

I got a ppt from a coworker with some drawings in them. The drawings are
missing some of the text (but not all). If I double click the drawing (as if
to edit it) the Visio edit window opens and the text is there. I then click
back on the slide. The Visio window closes and the text is visible in the
drawing. If I save the ppt, the next time I open it, the text will be
visible. If I close without saving, the text will still be missing. I have
to "edit" each drawing in the file to get all the text.
I have Visio Standard 2003 and powerpoint 2003 sp3 on Windows XP SP2